Uploaded a small utility called Blinkenwords on RubyForge. It's a simplistic RSVP (rapid serial visual presentation) program which takes input from the clipboard (shortcut: up arrow key) and displays it (shortcut: down arrow key) in vertical chunks. You can change the number of words in each block (from 1-10 at a time) and change the speed in words per minute (shortcuts: -5 wpm => [, +5 wpm => ]).
Whether reading this way helps or hinders speed and comprehension is questionable (see this blog post I wrote a while back on the topic of speed reading), so this is pretty experimental and YMMV (if you can even get it working - had some troubles with source file encodings and a couple of other things). Personally, I find it useful when there's lots of drudgery-reading to be done (e.g. catching up on forums/lengthy emails/news articles), but have problems with difficult, dense texts.
Update: You can download a Windows build of Blinkenwords is here. I used a very impressive program called OCRA to automatically bundle the Ruby interpreter and required libraries into a single 4mb(not enormous) packed executable.